type calcFnType = (num1: number, num2: number) => number
function calc(calcFn: calcFnType) {
    const num1 = 100
    const num2 = 200
    console.log(calcFn(num1, num2));
}

calc(function () {// 不校验   匿名函数
    return 123
});

// foreach 例子
[1, 2, 3, 4].forEach(() => {// 不报错

});

export { }